Maxfield, John E. <br/><br/>
Keys to mathematics 
[by] John E. Maxfield and Margaret W. Maxfield. 
 - Philadelphia  Saunders  1973. 
 - ix, 328 p.  illus.  26 cm. 
<br/><br/><label>ISBN: </label>0721661939 
<br/><br/><label>LCCN: </label>72086450 //r892 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematics
<br/><br/><label>LC Class. No.: </label>QA39.2  / .M4 
<br/><br/><label>Dewey Class. No.: </label>510